1. Field
This application relates generally to communications, and to traffic classified into different types transmitted over different sub-networks.
2. Background
An electronic device may support one or more communication protocols to transmit information to and receive information from other electronic devices. For example, a mobile device may support a wireless protocol such as IEEE 802.11 to communicate over airwaves with another device. Under 802.11, an access point may define one or more basic service sets for communicating with one or more sets of wireless stations. Here, each basic service set is defined by a unique basis service set identifier (“BSSID”). A device may thus communicate with another device via a given basic service set by including the corresponding basic service set identifier in each frame sent to the other device.
In wireless applications it is desirable to increase the amount of time a mobile device may be operated between battery recharges. In general, a mobile device operates in one of two states. Talk-time generally refers to the time the mobile device is actively engaged in sending or receiving user traffic such as when a call is in progress. Standby time generally refers to the time the mobile device is not in active communication but is not completely turned off. During standby time the mobile device may still transmit and receive certain types of traffic such as signaling. A conventional method of increasing operating time of a mobile device is to incorporate a relatively large battery into the mobile device. Unfortunately, this method may be both costly and inconvenient for a user of the mobile device.
A communication protocol such as those in the IEEE 802.11 family may support power savings in a wireless communication device by defining procedures that enable a mobile device to transition to a power save mode when it is not actively transmitting or receiving data. For example, an 802.11-based access point that provides traffic frames to a mobile device may buffer the frames when the mobile device is in the power save mode. In addition, the 802.11 family of protocols defines procedures that enable the mobile device to, upon transitioning from the power save mode to a normal operating mode, access a communication channel to receive frames from and transmit frames to the access point.
For downlink broadcast or multicast traffic, the access point will temporarily buffer the traffic in the event any mobile device in a given basic service set is in the power save mode. In this case, the access point will transmit the broadcast or multicast traffic to the mobile devices in the basic service set at predefined intervals. Thus, any mobile device in a power save mode may wake at the predefined intervals to receive the buffered broadcast or multicast traffic for that basic service set.
In some applications the user of a given mobile device may only wish to receive some of the broadcast or multicast traffic. However, in conventional 802.11-based approaches, the mobile device is configured to wake from the power save mode at every designated interval to ensure that the user receives all of the broadcast or multicast traffic of interest. As a result, standby time of the mobile device may be reduced due to the need to awaken and receive what may often be unwanted traffic.